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KVM: s390: get rid of gmap_fault()

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All gmap page faults are already handled in kvm by the function
kvm_s390_handle_dat_fault(); only few users of gmap_fault remained, all
within kvm.

Convert those calls to use kvm_s390_handle_dat_fault() instead.

Remove gmap_fault() entirely since it has no more users.

Acked-by: Janosch Frank <frankja@linux.ibm.com>
Reviewed-by: Christoph Schlameuss <schlameuss@linux.ibm.com>
Link: https://lore.kernel.org/r/20250123144627.312456-8-imbrenda@linux.ibm.com
Signed-off-by: Claudio Imbrenda <imbrenda@linux.ibm.com>
Message-ID: <20250123144627.312456-8-imbrenda@linux.ibm.com>
This commit is contained in:
Claudio Imbrenda 2025-01-23 15:46:19 +01:00
parent 3762e905ec
commit 6eb84e1300
3 changed files with 2 additions and 127 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

1
arch/s390/include/asm/gmap.h
View File

@ -113,7 +113,6 @@ int gmap_unmap_segment(struct gmap *gmap, unsigned long to, unsigned long len);
unsigned long __gmap_translate(struct gmap *, unsigned long gaddr);
unsigned long gmap_translate(struct gmap *, unsigned long gaddr);
int __gmap_link(struct gmap *gmap, unsigned long gaddr, unsigned long vmaddr);
int gmap_fault(struct gmap *, unsigned long gaddr, unsigned int fault_flags);
void gmap_discard(struct gmap *, unsigned long from, unsigned long to);
void __gmap_zap(struct gmap *, unsigned long gaddr);
void gmap_unlink(struct mm_struct *, unsigned long *table, unsigned long vmaddr);

4
arch/s390/kvm/intercept.c
View File

@ -368,7 +368,7 @@ static int handle_mvpg_pei(struct kvm_vcpu *vcpu)
reg2, &srcaddr, GACC_FETCH, 0);
if (rc)
return kvm_s390_inject_prog_cond(vcpu, rc);
rc = gmap_fault(vcpu->arch.gmap, srcaddr, 0);
rc = kvm_s390_handle_dat_fault(vcpu, srcaddr, 0);
if (rc != 0)
return rc;
@ -377,7 +377,7 @@ static int handle_mvpg_pei(struct kvm_vcpu *vcpu)
reg1, &dstaddr, GACC_STORE, 0);
if (rc)
return kvm_s390_inject_prog_cond(vcpu, rc);
rc = gmap_fault(vcpu->arch.gmap, dstaddr, FAULT_FLAG_WRITE);
rc = kvm_s390_handle_dat_fault(vcpu, dstaddr, FOLL_WRITE);
if (rc != 0)
return rc;

124
arch/s390/mm/gmap.c
View File

@ -607,130 +607,6 @@ int __gmap_link(struct gmap *gmap, unsigned long gaddr, unsigned long vmaddr)
}
EXPORT_SYMBOL(__gmap_link);
/**
* fixup_user_fault_nowait - manually resolve a user page fault without waiting
* @mm: mm_struct of target mm
* @address: user address
* @fault_flags:flags to pass down to handle_mm_fault()
* @unlocked: did we unlock the mmap_lock while retrying
*
* This function behaves similarly to fixup_user_fault(), but it guarantees
* that the fault will be resolved without waiting. The function might drop
* and re-acquire the mm lock, in which case @unlocked will be set to true.
*
* The guarantee is that the fault is handled without waiting, but the
* function itself might sleep, due to the lock.
*
* Context: Needs to be called with mm->mmap_lock held in read mode, and will
* return with the lock held in read mode; @unlocked will indicate whether
* the lock has been dropped and re-acquired. This is the same behaviour as
* fixup_user_fault().
*
* Return: 0 on success, -EAGAIN if the fault cannot be resolved without
* waiting, -EFAULT if the fault cannot be resolved, -ENOMEM if out of
* memory.
*/
static int fixup_user_fault_nowait(struct mm_struct *mm, unsigned long address,
unsigned int fault_flags, bool *unlocked)
{
struct vm_area_struct *vma;
unsigned int test_flags;
vm_fault_t fault;
int rc;
fault_flags |= FAULT_FLAG_ALLOW_RETRY | FAULT_FLAG_RETRY_NOWAIT;
test_flags = fault_flags & FAULT_FLAG_WRITE ? VM_WRITE : VM_READ;
vma = find_vma(mm, address);
if (unlikely(!vma || address < vma->vm_start))
return -EFAULT;
if (unlikely(!(vma->vm_flags & test_flags)))
return -EFAULT;
fault = handle_mm_fault(vma, address, fault_flags, NULL);
/* the mm lock has been dropped, take it again */
if (fault & VM_FAULT_COMPLETED) {
*unlocked = true;
mmap_read_lock(mm);
return 0;
}
/* the mm lock has not been dropped */
if (fault & VM_FAULT_ERROR) {
rc = vm_fault_to_errno(fault, 0);
BUG_ON(!rc);
return rc;
}
/* the mm lock has not been dropped because of FAULT_FLAG_RETRY_NOWAIT */
if (fault & VM_FAULT_RETRY)
return -EAGAIN;
/* nothing needed to be done and the mm lock has not been dropped */
return 0;
}
/**
* __gmap_fault - resolve a fault on a guest address
* @gmap: pointer to guest mapping meta data structure
* @gaddr: guest address
* @fault_flags: flags to pass down to handle_mm_fault()
*
* Context: Needs to be called with mm->mmap_lock held in read mode. Might
* drop and re-acquire the lock. Will always return with the lock held.
*/
static int __gmap_fault(struct gmap *gmap, unsigned long gaddr, unsigned int fault_flags)
{
unsigned long vmaddr;
bool unlocked;
int rc = 0;
retry:
unlocked = false;
vmaddr = __gmap_translate(gmap, gaddr);
if (IS_ERR_VALUE(vmaddr))
return vmaddr;
if (fault_flags & FAULT_FLAG_RETRY_NOWAIT)
rc = fixup_user_fault_nowait(gmap->mm, vmaddr, fault_flags, &unlocked);
else
rc = fixup_user_fault(gmap->mm, vmaddr, fault_flags, &unlocked);
if (rc)
return rc;
/*
* In the case that fixup_user_fault unlocked the mmap_lock during
* fault-in, redo __gmap_translate() to avoid racing with a
* map/unmap_segment.
* In particular, __gmap_translate(), fixup_user_fault{,_nowait}(),
* and __gmap_link() must all be called atomically in one go; if the
* lock had been dropped in between, a retry is needed.
*/
if (unlocked)
goto retry;
return __gmap_link(gmap, gaddr, vmaddr);
}
/**
* gmap_fault - resolve a fault on a guest address
* @gmap: pointer to guest mapping meta data structure
* @gaddr: guest address
* @fault_flags: flags to pass down to handle_mm_fault()
*
* Returns 0 on success, -ENOMEM for out of memory conditions, -EFAULT if the
* vm address is already mapped to a different guest segment, and -EAGAIN if
* FAULT_FLAG_RETRY_NOWAIT was specified and the fault could not be processed
* immediately.
*/
int gmap_fault(struct gmap *gmap, unsigned long gaddr, unsigned int fault_flags)
{
int rc;
mmap_read_lock(gmap->mm);
rc = __gmap_fault(gmap, gaddr, fault_flags);
mmap_read_unlock(gmap->mm);
return rc;
}
EXPORT_SYMBOL_GPL(gmap_fault);
/*
* this function is assumed to be called with mmap_lock held
*/